1. Field of the Invention
The present invention relates to a novel organic compound and an organic light-emitting device using the same.
2. Description of the Related Art
The recent progress of an organic light-emitting device is significant, and the device suggests its potential to find use in a wide variety of applications because of the following reasons. The device shows high luminance at a low applied voltage. In addition, the device has a variety of emission wavelengths. Furthermore, the device can be a thin, light-weight light-emitting device with high-speed response.
However, at present, additional improvements in: initial characteristics such as emission efficiency; and duration characteristics against, for example, luminance degradation due to light emission for a long period of time have been needed. The initial characteristics and duration characteristics result from all layers constituting the device including a hole injection layer, a hole-transporting layer, a light-emitting layer, a hole-blocking layer, an electron-transporting layer, and an electron injection layer.
Examples of the hitherto known material to be used in the hole-blocking layer, the electron-transporting layer, or the electron injection layer includes, a phenanthroline compound, an aluminum quinolinol complex, an oxadiazole compound, a triazole compound, or an azole compound. There have been a relatively large number of reports each concerning the use of the azole compound out of them in a light-emitting layer, an electron-transporting layer, or an electron injection layer. Each of Japanese Patent Application Laid-Open Nos. 2005-082703, 2001-335776, 2001-326079, 2001-97961, 2001-97962, 2000-113985, H11-345686, H10-340786, and H05-214335 discloses an organic electroluminescent device using a benzoxazole compound or a heterocyclic compound having an imidazolopyridine skeleton in a light-emitting layer or an electron-transporting layer. However, the duration characteristics and initial characteristics of an EL device of each of those documents are not sufficient, and, in particular, there still remains an unsolved problem of drive at a low voltage.